Constant resistance shock absorbing device



Jan. 24, 1956 v. F. DE VOsT ETAL 2,732,040

CONSTANT RESISTANCE SHOCK ABSORBING DEVICE Filed March 25, 1953 FIG.l.

6 l6 l8 2| 2o 9 INVENTOR VALMORE F DEVOST JONATHAN O. FISHER BY jaw/5ATTORNEYS Jar- United States PatentO A 1,732,040 CONSTANT RESISTANCESHOCK ABSORBING' DEVICE Valrnore F. De Vost, Washington, D. (L, andJonathan C. Fisher, Riverdale, Md., assignors to the United States ofAmerica as represented by the Secretary of the Navy Application March23, 1953, Serial No. 344,255 g 6. Claims. (Cl. 188-101) (Granted underTitle 35, U. s. Code 1952 see. 266) The invention described herein maybe, manufactured and used by or for the Government of the United Statesof America for governmental purposes without the payment of anyroyalties thereon or therefor.

The present invention relates to a new and improved constant resistancestopping element and more particularly to a high energy shock absorptiondevice suitable for use with an impact apparatus.

Heretofore, stopping elements such, for example, as lead pads of varyingtypes and diameters were mounted on an anvil and interposed between thestriking surface of the movable carriage or test vehicle to give somecontrol over the duration of the shock'when the carriage forcibly struckthe lead pads.

In actual practice such devices have not proven entirely satisfactoryfor the reasons that after each drop test it was necessary to remove thepads from the test machine and remould them for subsequent use whichinvolved considerable time and expense. Furthermore, with such padarrangements it has been found that the duration of the accelerationtime pulsesproduceable at velocity changes less than 25 feet per secondwere entirely too short and the pulse shape at high' velocities were notconsistant or smooth. 7

The present invention contemplates the provisionof a new and improvedstop device which overcomes all the disadvantages of the prior artdevices and which is emcient and economical in operation, reproduceable,and further provides means of absorbing considerable high energy withrelatively constant resistance producing decelerations up to 500 g.,from to 100 milliseconds duration.

An object of the present invention is to provide a new and improvedconstant resistance stopping device suitable for an apparatus ormechanism requiring high energy absorption and reproduceableacceleration time pulses.

Another object of the invention is the provision of a cushioning deviceadaptedto absorb energy with relatively constant resistance.

Still another object of the invention is the provision of absorptiondevice for controlling the shock durations of an accelerated vehicle.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein: t

Fig. 1 is an elevational view of the device of the present invention inaccordance with a preferred embodiment thereof;

Fig. 2 is a central longitudinal sectional view taken on the line 2--2of Fig. 1;

Fig. 3 is a central longitudinal sectional view of an alternatearrangement of the device of Fig. 1; and,

Fig. 4 is a central longitudinal sectional view of another arrangementof the stopping device.

Referring now to the drawings wherein like reference charactersdesignate like parts throughout the several views and more particularlyto Fig. 1 thereof, the numeral 10 generally indicates" the constantresistance stopping device. The device comprises a cylindrical container11 formed of any yieldable material suitable for the purpose such, forexample, as rubber'or the like.

The container 11 has formed thereon at the impact receiving end thereofa conical portion 12, the apex 13 thereof being adapted to receive theimpact of a movable object thereby to control the shock durationthereof. While the aforesaid device may be employed with any apparatusor machine requiring high energy absorption and reproduceableacceleration time pulses it is particularly adapted for use in a testmachine such, for example, as the type similar to the device shown andclaimed in the copending application of John H. Armstrong et al., filedMarch 27, 1953, Serial No. 345,272 and titled Drop Tester.

As more clearly shown on Fig. 2, the stopping device is provided withabase plate generally indicated by the reference character 14,comprising a flange 15 having a centrally disposed boss 16 integrallyformed therewith and snugly fitted within the open end of the container11, the container being filled as at 17 with sand shot or any othersuitable dense particulate medium. The base plate 14 is provided with acentrally disposed well or bore 18, threaded as at 19 for threadedengagement with a plug or compressing element 20. By the plugarrangement the material 17 may be thoroughly packed within thecontainer without the formation of any air pockets therein as the plug20 is threaded into the bore 18, the plug acting as a ram to force theaforesaid materials into engagement with the inner wall of thecontainer. The plug 20 has formed therein a socket 21 for a suitablewrench or tool thereby to facilitate threading of the plug into the bore18.

As shown more clearly on Fig. 2, the lower end portion of the container11 is clamped to the boss 16 by a split ring or strap 22, the strapcomprising a pair of mutually spaced ears 23 and a clampingbolt 24whereby the strap may be drawn sufficiently tight to clamp the containerto the boss 16.

The stopping element may be employed with any type of mechanismrequiring high energy absorption and reproduceable acceleration timepulses and the energy absorption rate thereof may be regulated, ifdesired, by increasing or decreasing the thickness ofthe cylindricalwall of the container or by increasing or decreasing the resistancecharacteristics of the rubber.

In regard to Fig. 3, it will be noted that the general arrangementthereof is similar to the device of Fig. 1. However, to increase theabsorption rate and resistance characteristics of the device thecontainer 11 thereof is provided with a plurality of resilient bands orsleeves 25 composed of any material suitable for the purpose such, forexample, as rubber or the like. The bands or sleeves are arranged oneabout the other and disposed about the container, the length thereofbeing the same as the length of the parallel wall of the container 11.In this arrangement it will be understood that by increasing ordecreasing the number of bands 25, the absorption rate of the device ofFig. 3 may be controlled.

Referring to Fig. 4 the device comprises a container 26 having a roundedor semispherical impact end portion 27. A tubular element or sleeve 28is disposed about the container 26, the aforesaid container and sleevebeing composed of any suitable resilient material such, for example, asrubber or the like. In the device of Fig. 4, it will be noted that thebase plate, plug and split strap arrangement is identical to thestructure disclosed in Figs. 2 and 3, the split strap being adapted toclamp the container 26 and sleeve 28 to the boss 16. Furthermore, toincrease the absorption rate of the device of Fig. 4 the container 26 isfilled with pellets 29 composed of any metallic material suitable forthe purpose such, for example, as

brass, lead, iron, or the like shot. The wire elements 31 are wound orotherwise disposed about the sleeve 28. The pellets may be of uniformsize, or varying sizes depending upon the energy absorptioncharacteristics desired. Furthermore, if desired, the aforesaidcontainers may be filled withv metallic shavings, or a viscous liquidsuch as heavy oil or mercury.

The stopping device herein described provides means of absorbing a largeamount of energy with relatively constant resistance, producingdecelerations of the desired magnitude and duration in response toimpact of a test vehicle or other moving body therewith. Furthermore, abody striking the stopping device axially at high velocity will besubjected to a negative acceleration characterized by a time pulserectangular in shape and varying in magnitude dependant upon thestriking velocity of the body and the resistance characteristics of thestopping device. The energy absorption rate may be related, if desired,by increasing or decreasing the resistance characteristics of the rubberby varying the wall thickness thereof or by varying the filler 11 or 29.

The constant resistance stopping devices of this invention are admirablysuited for use with an accelerated test vehicle such, for example, asthe type used in a drop test machine producing acceleration time pulsesresulting in velocity changes of 80 feet per second. Furthermore, whilethe stopping devices have been described with particular reference to adrop tester it will be obvious from the foregoing that the device may beemployed with any type of vehicle or mechanism requiring high energyabsorption and reproduceable acceleration-time pulses.

From the foregoing, it will be apparent that a new and improved stoppingmeans has been devised for absorbing high energy shocks with relativelyconstant resistance for the duration of the shock.

Obviously many other modifications and variations of the presentinvention are possible in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent inthe United States is:

1. A constant resistance shock absorbing device of the characterdisclosed comprising a cylindrical container characterized byelasticity, a particulate mass disposed within and filling saidcontainer, a base plate, a centrally disposed boss integral with saidbase plate and disposed within one end of the container, means includinga strap disposed about one end of the container for clamping thecontainer to the boss, and an adjustable ram in engagement with saidmass and in threaded engagement with said boss for packing the masssufiiciently to cause the container to be filled therewith.

2. A constant resistance shock absorbing device of the characterdisclosed comprising a cylindrical container composed of resilientmaterial, a particulate mass disposed within and filling said container,a plurality of resilient sleeves disposed about said container, a baseplate, a centrally disposed boss integral with said base plate andarranged within one end of the container, and means including a strapclamped about said sleeves for clamping the sleeves and container tosaid boss.

3. A constant resistance shock absorbing device of the characterdisclosed comprising a cylindrical container composed of resilientmaterial, a particulate mass disposed within' and filling saidcontainer, a plurality of resilient sleeves disposed about saidcontainer, a base plate for supporting said sleeves and container, acentrally disposed boss integral with said base plate and arrangedwithin one end of the container, means including a strap clamped aboutsaid sleeves for clamping the sleeves and container to said boss,clamping means for said strap, and adjustable means in engagement withsaid mass for compressing the mass sufiiciently to cause the mass tocompletely fill the container in response to movement of said adjustablemeans.

4. A device of the character disclosed comprising a container filledwith a particulate mass for absorbing high energy shocks resulting fromimpact of an accelerated body therewith and havingrelatively constantresistance to said shock, resilient means on said container forincreasing the absorption rate of said container, a base plate forsupporting said container and resilient means, a centrally disposed bossintegral with said base plate and disposed within one end of thecontainer, means including an annular strap in engagement with saidresilient means for clampingthe resilient means and container to saidboss, and a ram in threaded engagement with the boss and disposed withinthe container for compressing the mass sufficiently to cause the mass tocompletely fill the container as the ram is threaded into said boss.

5. A device of the character disclosed comprising constant shockresisting container composed of elastic material having a particulatemass disposed therein and filling said container, means including anelastic sleeve in engagement with and encompassing the container forincreasing the shock resisting characteristics of the container, meansincluding a base plate for supporting said container and sleeve, and aram in threaded engagement with the base plate and disposed within thecontainer in engagement with said mass for compressing the masssufficiently to cause the mass to completely fill the container as theram is threaded into the base plate.

6. A device for absorbing high energy shocks resulting from impact of anaccelerated body therewith and having relatively constant resistance tosaid shocks comprising a cylindrical container composed of elasticmaterial, a particulate mass disposed within and filling said container,a sleeve composed of elastic material disposed about said container forincreasing the absorption rate of said device, a flexible element woundabout said sleeve for controlling the elastic characteristics of saidsleeve, supporting means for said container and sleeve, and means forclamping the container and sleeve to said supporting means.

References Cited in the file of this patent UNITED STATES PATENTS1,526,015 Sanner Feb. 10, 1925 2,380,899 Strachovsky July 31, 19452,457,205 Campbell et al Dec. 28, 1948 2,555,436 Druilhet June 5, 19512,656,711 Tschudi Oct. 27, 1953 FOREIGN PATENTS 18,213 Great BritainAug. 11, 1911 40,052 Austria Dec. 10, 1909

